Mozilla Corp. has released the first preview of Firefox 3.1, the fast-track update that the open-source company has pegged with a late 2008 or early 2009 ship date. Code-named "Shiretoko," named for a national park on Japan's northern-most island of Hokkaido, Firefox 3.1 Alpha 1 was delayed several days because of a last-minute bug found in the Mac OS X version.

Firefox 3.1 Alpha 1 includes some, but not all, of the features Mozilla hopes to add to the update as work continues. Among the noticeable changes: several improvements to the address bar, which Mozilla dubs the "Smart Location Bar" in recognition of the search enhancements it received in Firefox 3.0; and changes to tab-switching.

Pressing Ctrl-Tab in Alpha 1 switches between current and last-viewed tabs rather than simply moving to the next tab to the right. Thumbnails of each page are also now displayed for easier recognition. Like many of the features slated for Firefox 3.1, the revised tab-switching was originally meant to be included with Firefox 3.0, but had been dropped during development to keep that June version on schedule.